The present invention relates to liquid hydrocarbon cleanup and recovery system using sorbents, and more specifically, but not by way of limitation, to a reusable two-part sorbent pad chemically treated to enhance its ability to rapidly soak up and hold liquid hydrocarbons and repel water. The term liquid hydrocarbons refers to oil and other petroleum products and will be referred to throughout as oil.
The ecological disasters resulting from oil spills have created a great need for effective cleanup systems. Present cleanup systems include booms, dispersants, thickeners, skimmers, and sorbents.
Booms are mechanical barriers which contain and concentrate spilled oil. They are available in various sizes and shapes used to encircle a spill, floating with a portion above and below the water surface to keep oil from splashing over or escaping beneath. Booms are used mainly for containment, and do not sufficiently contribute to the recovery and cleanup of the spilled oil. Additionally, because booms serve as containment systems, much of the spilled oil sinks to the bottom, precluding recovery, damaging undersea life, and forming tar balls which wash up on shore.
Dispersants are generally liquid chemicals which when applied to the surface of the spill accelerate the dispersal of the oil by reducing the surface tension between the oil and the water. However, some of these chemicals are toxic, and therefore, must be used judiciously. Dispersants are costly and do little to help the environment since the volatiles are released to the atmosphere. Although the concentrated spill has been dispersed, the oil itself remains in the water.
Thickeners or herding agents thicken the oil by increasing the surface tension between the oil and the water, which reduces the spreading of the spill and permits easier cleanup, however, thickeners are expensive, and some thickeners are toxic. In addition, the thickened oil will sink sooner than oil that has not been treated. Once the oil sinks, any cleanup at the surface is precluded.
Skimmers mechanically remove the spilled oil from the surface of the water. The basic types include: vacuum, gravity, oleophilic, and centrifugal skimmers. Skimmers operate to separate the oil from the water, however, most skimmers are inefficient and leave much of the recovered oil mixed with water, thereby making oil recycling expensive and economically impractical.
Although the above systems do operate to reduce the ecological damage created by oil spills, they provide only a partial solution. Dispersants provide little solution because they merely disperse the oil without removing it from the environment. Containment systems and thickeners also do not remove the oil, but instead must be used with a removal system such as a skimmer. All four systems are expensive which makes them economically impractical. Most importantly, however, all four systems are ineffective for large oil spills and will not function properly in bad weather, accompanied by very rough seas.
Another type of oil cleanup system is sorbents. Sorbents function to soak up surface oil when placed on an oil spill. The sorbents recover the spilled petroleum by either adsorption, in which the petroleum is attracted to the sorbent surface and then adhered to it, or absorption, in which the petroleum penetrates the pores of the sorbent material. Sorbents are generally marketed in particulate form for spreading over a slick or as sheets, rolls, pillows, or booms. Sorbent material may consist of natural products, such as feathers, peat or straw; mineral compounds, such as ash, vermiculite, or perlite; and most commonly synthetic products, such as polyethylene or polypropylene. Although more effective than the above systems, typical sorbents are frequently not reusable, and are ineffective when it is desired to recycle the oil. Once sorbents are used to soak up the oil spill, they present a disposal problem. Most sorbents when saturated are presently disposed of by burying them in approved landfills or by burning them in accordance with local regulations. Both methods are ecologically injurious and statutes, both state and federal are being enacted to limit such activity.
Accordingly, the sorbent pad of the present invention has been constructed to be highly reusable, to be effective even in the roughest water, to recover the greatest amount of oil and permit the recycling of recovered oil. The sorbent pad of the present invention provides both an ecological and economic advantage over conventional oil spill cleanup systems.